Just David Walliams

Tuesday 2 November 2010 10:17 BST

David Walliams arrives at Soho House bang on time for our interview to promote Billionaire Boy, his latest children's book, just published, about a fat, rich 12-year-old boy who gets bullied at school. The publicist at HarperCollins has made it clear from the outset that this must be a "bookcentric" interview and that the 39-year-old, cross-Channel-swimming, cross-dressing Little Britain comedian-turned-superstar won't talk about some subjects, which I assume means life with his new wife, supermodel Lara Stone, her rehab for alcoholism and whether or not he's gay.

Still, without any prompting, while being photographed — in sober navy wool suit and open-necked pink shirt — Walliams launches into a gentle tirade against the journalist who has just written that at their May wedding (a lavish affair at Claridge's), "toasts were made with popcorn rather than champagne in deference to the bride's sobriety".

"No, we didn't," he exclaims, his face — which alternates between impassive composure when he's being serious and animated camp when he's not —lighting up. "It's totally made up. There were drinks. Yes, Lara doesn't drink but everyone else had them. And because of the way the internet works, it becomes, like, well some journalists — obviously not you — but some, they just copy as fact."

Yet a moment later, he dismisses it as "harmless really", indignant at the mistake but pleased at how many column inches he and his Dutch wife have been clocking up between them. Even the question of whether they want "gay babies" has been grabbing headlines.

Walliams doesn't express any preference himself but concedes that Stone — to whom he proposed marriage after a brief courtship and a string of relationships with some famously gorgeous laydees — has changed his life. "It's lovely now because I start to think about the future in a way I hadn't before. The future was always work. I like working but it's not nourishing in the way that being in love with someone is nourishing. It's a great thing being married and being able to have a discussion, like, you know, shall we have some children and when. You don't need to go out, a great night could be staying in watching The X Factor."

Whether together or apart, at home in Belsize Park or out and about, London's hottest couple are everywhere. Earlier this year Stone signed a modelling contract with Calvin Klein for three of its labels and she is this month's Vogue cover girl, while Walliams has been gracing the nation's TV screens and billboards with co-star Matt Lucas in Little Britain mode for a big Nationwide Building Society ad campaign, billed "Proud to be Different".

They have also just finished filming a new series for the BBC together called Come Fly With Me: six half-hour comic episodes, going out at Christmas, about life in an airport. Lucas and Walliams play about 20 characters each — from airline owner to lavatory cleaner. "It's exciting because it's a completely new chapter in our careers — a whole new world; there's no overlap with Little Britain in terms of characters."

Both with Lucas, whom he originally met at the National Youth Theatre, and solo, Walliams anticipates a long career that extends far beyond Little Britain. "Look, we've made one successful comedy series together. That's good," Walliams pauses, "but I don't think you can live your whole life on that."

He'd like to work onstage again to recapture the success he had in 2008, playing in Harold Pinter's No Man's Land. "I got a real kick out of working with Michael Gambon in the West End.

Harold Pinter died during the time we were running. It was an incredible interlude in my life, where I was performing with one of the world's greatest actors who I've admired since I was a child, and meeting the world's greatest living (at the time) playwright. So it was like, how did that happen?"

Paradoxically, the man who is known for pushing boundaries and offending people in his comic sketches is almost reverential when talking about stage actors, and he clearly has a burning ambition and the potential to conquer stage acting.

"I'd love to do a play again and learn. I know I wasn't a skilled dramatic actor but I want to learn from the master. I went to see Simon Russell Beale the other night in Death Trap. If I got the chance to work with someone like him or Derek Jacobi or Judi Dench or Maggie Smith ..."

He trails off, lost in thought. Stage acting, he continues, is more challenging than anything filmed because "you're trying to formulate a performance that you're going to repeat night after night and there's a much longer rehearsal process."

Surely it also requires a lot more physical stamina? "Well, it's not going down a mine, is it?" he chuckles. "Or swimming the Channel. That was hard work." In fact the 2006 swim, which raised more than £1 million in aid of Sport Relief, was the toughest physical thing he's ever done.

"Training in the North Sea in December. Your body shakes uncontrollably from the cold, which makes it miserable. I do enjoy swimming now and yeah, I do exercise, but people think that because I did that one sporty thing I'm some sort of athlete. I get in a taxi and the driver says [Walliams's voice deepens] You doin' anything in the Olympics, David?...' I'd like to do something else like that but if you mark yourself out, you just get asked again and again. I could have failed to swim the Channel and I could now be the butt of jokes on panel shows. But to achieve something like that does make you more positive."

For all his achievements and success — critical and material — Walliams seems surprisingly insecure, starstruck even by his own stardom. He appears to want to be liked, to have approval. When I tell him how much the jokes in Billionaire Boy made me laugh, he replies graciously and sincerely: "Oh thank you, that's a good start."

He believes he would not have got the book deal or done a lot of other things, including sitting in this interview, had it not been for the success of Little Britain. "I suppose when it started on TV, that was a big throw of the dice for Matt and me ... I'm interested in what people think of my work and I read reviews. I'll read this interview and see if you liked me or not." He laughs but he's deadly serious.

For while Walliams may be quite svelte nowadays, he was once, and in some ways remains, that unconfident 12-year-old boy, Joe Spud, in Billionaire Boy, the fat kid with no friends who almost came last in the cross-country race at school and got laughed at by everyone else. He is also Dennis, the frock-wearing bully victim in his first book, The Boy in the Dress, just as he is Chloe, the lonely 12-year-old girl heroine in his second book, Mr Stink. You feel, and it's rather touching, that he can't quite believe how he got to be where he is: rich and famous, mates with the rich and famous.

Unlike billionaire's son Joe Spud, he had a suburban upbringing in Surrey. He went to the fee-paying Reigate Grammar, his late father was a civil engineer for London Transport and his mother was a laboratory technician at Sutton Grammar. Although he has a sister two years older, now a primary school teacher, Walliams describes his childhood as mostly solitary. "I liked spending time on my own with my imagination."

Like Joe, however, Walliams has discovered that self-made wealth — he is reported to have earned £1.8 million so far this year — has its problems.

He says: "I wouldn't have written this book if I hadn't become wealthy and successful. Friends don't fall away but you notice people change in a slightly different way around you. You have a kind of power. It's weird."

To date, the books, which are engagingly rude and funny in a Little Britain-lite kind of way, have only featured heroes who are 12. "It's a good age, the last age before you reach puberty. I think I'd find it too complicated to write about that experience, being, like, a teenager and, you know, having those kind of feelings."

His first two books so far have sold about 140,000 copies and both have been nominated for the Roald Dahl Funny Prize. Walliams is delighted because it vindicates him as a writer.

"There's a credibility issue when you're already well-known and you write a book, because other people have degraded books by just putting their name to them but not actually having written it. Obviously I'm already a writer, so that's appropriate but in articles I often get lumped in with those people, like, celebrities Katie Price and David Walliams' ... but I've actually written it."

As the interview ends, the publicist hands Walliams the latest copy of Heat magazine. In another publicity push for the book, Walliams has posed naked, blondly bewigged and painted in gold, apparently dead on a bed, Bond girl-style. Silence follows as he becomes utterly absorbed in reading his interview about "married life, his X Factor obsession and how to swear in Dutch". I want to tell the publicist that it wasn't my fault we talked about all those other things.

Billionaire Boy, illustrated by Tony Ross, is published by HarperCollins (£12.99); David Walliams will be signing books at Foyles, St Pancras station, on November 18 at 5pm. One child will get to be a billionaire for a day, including having tea with David. See billionaireboybook.com